1. City lay down a marker

Manchester City are, according to Roberto Di Matteo and other well-placed judges, the team to beat in this season's Premier League, and not only because of their status as defending champions. As they produced a devastating three-goal salvo in 12 second-half minutes here, it was easy to be impressed. Di Matteo's Chelsea had been reduced to 10 men, following Branislav Ivanovic's reckless lunge at Aleksandar Kolarov, but there was a cut and thrust about City that suggested that, after a positive pre-season on the field, they are ready to hit the ground running.

Sergio Agüero was busy and eye-catching up front, apart from his dreadful injury-time miss, while the goals from Yaya Touré, Carlos Tevez, in particular, and Samir Nasri were of the highest order. Tevez deserved his ovation when he was substituted late on. It remains to be seen whether Roberto Mancini will reuse an experimental defensive formation, with three men in the middle or, for that matter, Stefan Savic, who was withdrawn at half-time. The back-up goalkeeper, Costel Pantilimon, did his prospects no good when he fumbled to allow Chelsea back to 3-2. Yet there was plenty in City as an offensive force to inspire confidence.

2. Chelsea have lots more to play for

The septuple dream has died. But, as any Chelsea player will tell you, there remain six glittering prizes to play for this season, including the European Super Cup and the World Club Cup. Nobody was getting too vexed about what is, effectively, a pre-season fixture. Exciting challenges await. But Di Matteo's team will have to defend much better than they did here and they have done for patches of pre-season.

The manager, though, could point to having to play for 48 minutes with 10 men and the requirement to reshuffle his backline, with Ramires moved to right-back. What will grate is Ivanovic's three-match ban but, on the plus side, Fernando Torres took his goal in clinical fashion. What Di Matteo would give for more of the same at regular intervals during the season.

3. Blimey, football's back already

Everybody is agreed that the Olympics have been good for the soul and it feels as though there is a certain weariness about football's return. As the rain lashed down in the countdown to kick-off and the announcement of John Terry's name was jeered by the City fans, it was possible to consider a long nine months ahead. The Chelsea captain was condemned as a racist by City's support and his every touch was booed, as he was given a taster for what surely awaits him at away grounds this season.

There was play-acting here, back chat to the referee, Kevin Friend, aggro and fury over Ivanovic's red card. There were other poor tackles, too, and absolutely no charity. Ramires was very lucky to stay on. Welcome back football. You've been missed.

4. Hazard endures mixed fortunes

As the only new signing on display, it was inevitable that Eden Hazard would find himself under the spotlight. Chelsea's other buys were injured or unavailable – Oscar will play a friendly for Brazil in Sweden on Wednesday, on the back of his Olympic exertions, before he joins up with his new club, which is aggravating for Di Matteo.

And so Hazard, the £32m purchase from Lille, sought to strut his stuff. Started on the left flank, the Belgian is not afraid to attempt the outlandish, as some of his flicks demonstrated. There were small flashes of encouragement from him, although not when he failed to execute an extravagant backheel in the 20th minute and fell flat on his face. That was a horrible moment and his theatrical tumble earlier in the first half was not great, either. He will need time to settle to the pace of English football. It is fair to say that he will enjoy better afternoons.

5. City make a signing … at last

Mancini's grumbling over City's lack of activity on the transfer market and his scarcely concealed contempt for Brian Marwood, the football director, had provided one of the soundtracks to the club's summer. It had felt at odds with the euphoria of last May and the sight of thousands of City fans here proudly decked out in "Champions 2011-12" T-shirts. But in the countdown to kick-off, it emerged that Marwood had struck, with Jack Rodwell set to undergo a medical at the club, ahead of a proposed move from Everton.

It was possible to question whether Mancini had driven the signing, given his well-documented desire to sign Roma's Daniele De Rossi, the defensive midfielder who can also play at centre-half. City, though, have been keen to add young talents with the capacity to give years of service. Rodwell, who made his Everton debut at 16, has perhaps not made the expected progress and he suffered badly from injury in the second half of last season. But he will be fiercely determined to make his mark at City and he senses great opportunity.